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