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