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