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