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