One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,16)(12,14)(13,17)(15,19)(18,24)(20,22)(21,23)(25,26,30,33)(27,34,28,31)(29,37,38,32)(35,39,36,40)(1,2)(3,4)(5,7)(6,8)(9,11)(10,15)(12,16)(13,18)(14,19)(17,23)(20,24)(21,22)(25,26)(27,31)(28,34)(29,32)(30,33)(35,39)(36,40)(37,38) involution — undirected(1,3)(2,6)(4,7)(5,8)(25,27,30,28)(26,31,33,34)(29,35,38,36)(32,39,37,40)(1,4,5,6)(2,3,7,8)(9,12,14,10)(11,16,19,15)(13,17,22,20)(18,23,21,24)(25,26)(27,31)(28,34)(29,37)(30,33)(32,38)(35,40)(36,39)(1,3)(2,4)(5,8)(6,7)(9,11)(10,16)(12,15)(13,21)(14,19)(17,23)(18,22)(20,24)(25,28,30,27)(26,31,33,34)(29,35,38,36)(32,40,37,39)(1,2)(3,6)(4,8)(5,7)(9,13,14,22)(10,17,12,20)(11,18,19,21)(15,23,16,24)(25,29)(26,32)(27,35)(28,36)(30,38)(31,39)(33,37)(34,40)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.