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