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