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