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