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