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