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