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