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