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