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