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