One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,7)(5,8)(9,10,13,16)(11,17,19,14)(12,15,22,20)(18,24,21,23)(25,26)(27,34)(28,31)(29,37)(30,33)(32,38)(35,39)(36,40)(1,3)(2,4)(5,7)(6,8)(9,10)(11,14)(12,15)(13,16)(17,19)(18,23)(20,22)(21,24)(25,26)(27,34)(28,31)(29,32)(30,33)(35,40)(36,39)(37,38) involution — undirected(9,10)(11,14)(12,15)(13,16)(17,19)(18,23)(20,22)(21,24)(25,27,30,28)(26,31,33,34)(29,35,38,36)(32,39,37,40)(1,2,5,8)(3,6,7,4)(9,10)(11,14)(12,20)(13,16)(15,22)(17,19)(18,24)(21,23)(25,28,30,27)(26,31,33,34)(29,36,38,35)(32,39,37,40)(1,3)(2,6)(4,8)(5,7)(9,11,13,19)(10,14,16,17)(12,21,22,18)(15,24,20,23)(25,29,30,38)(26,32,33,37)(27,35,28,36)(31,39,34,40)(1,4,5,6)(2,7,8,3)(9,12,13,22)(10,15,16,20)(11,18,19,21)(14,23,17,24)(25,26)(27,31)(28,34)(29,37)(30,33)(32,38)(35,40)(36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.