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