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