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