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