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