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