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