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