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