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