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