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