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