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