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