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