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