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