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