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