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