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