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