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