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