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